The present invention relates to disposable plates and particularly to compartmented disposable food serving plates.
Disposable compartmented plates are known. There is disclosed in U.S. Pat. No. 1,848,066 to Shephard et al. a disposable paper plate with three compartments. According to the description, the article may be square or rectangular, divided into two, four or more equal or unequal compartments by partitions. Page 2, col. 1, lines 18-21; page 2, col. 2, lines 72-74. The ribs are generally V-shaped. See, also, Des. 169,133 to Foster which discloses a tray having compartments of varying size. So also, the following U.S. Design patents disclose plates, food trays and the like with non-symmetrical partitions: U.S. Des. Pat. No. 386,048 to Bebaway; U.S. Des. Pat. No. 316,800 to Wertheim; while U.S. utility Pat. No. 3,675,811 to Artz discloses a container with different sized compartments. Of general interest with respect to basket-like designs which may be utilized in accordance with the present invention are U.S. Design Pat. Nos: Des. 279,345 to Durand; U.S. Des. Pat. No. 190,336 to Denni et al.; U.S. Des. Pat. No. 179,011 to Kimble; U.S. Des. Pat. No. 140,345 to Fordyce; U.S. Des. Pat. No. 135,030 to Harshman; U.S. Des. Pat. No. 116,789 to Barbiers; U.S. Des. Pat. No. 109,494 to Leigh; U.S. Des. Pat. No. 106,554 to Wilson and U.S. Des. Pat. No. 88,688 to Thompson.
Articles with symmetrical compartments as opposed to non-symmetrical compartments are perhaps more common in the art, as may be seen in U.S. Design Pat. No. Des. 250,928 to Franklin; U.S. Des. Pat. No. 232,613 to Cheladze; U.S. Des. Pat. No. 221,290 to Weideman; U.S. Des. Pat. No. 351,316 to Mann; U.S. Des. Pat. No. 364,537 to Anderson; U.S. Des. Pat. No. 188,502 to Metzler; U.S. Des. Pat. No. 164,669 to Chaplin; U.S. Des. Pat. No. 41,986 to Smith; as well as in U.S. utility Pat. Nos. 3,001,665 to Tomarin; 2,928,567 to Davis; and 1,440,070 to Fry.
The asymmetric articles in accordance with the present invention offer particular advantages, such as increased rigidity and toughness as will be better understood from the description which follows.
Disposable three compartmented food serving plates in accordance with the present invention provide convenience by having differing volumetric capacities for each compartment section, increased product strength per weight ratio, and an ergonomic rim profile for ease of holding and carrying. These advantages are provided by a plate profile comprised of four radii and a nonsymmetrical compartmented divider with the preferred dimensional characteristics. The plate profile also provides a curvilinear rim surface onto which patterning can be applied for visual and tactile purposes.
Typical three compartmented food serving plates have two smaller compartment sections that are equal in volumetric capacity and compartmented dividers that are symmetric when viewed from the top of the plate. This invention, having three compartments with differing volumetric capacities, provides more food placement options to the user. For example, the user may choose the largest food compartment for the main entree, the medium compartment for a larger side item portion and the smallest compartment for a smaller side item portion.
Compartmented plates are often improperly designed and lack the rigidity necessary when carrying the plates with a food load. The lower rigidity plates when loaded with food and carried with one hand can have excessive product distortion/deflection resulting in food spillage. Even worse, the plate can buckle by hinging along the compartmented rib divider resulting in more severe product distortion/deflection and food spillage.
The three compartmented plate described in this invention disclosure has a rib divider design which provides greater rigidity to minimize product distortion/deflection and reduce the chances for food spillage. The angles between the compartmented rib dividers were chosen to reduce plate buckling or hinging while maintaining adequate sized food containing sections with differing capacities.
The compartmented rib divider cross-sectional geometry and intersection to the plate four radii profile are also unique and believed to contribute to the greater product rigidity and reduction in plate buckling. The plate of this invention disclosure has a rib cross-section consisting of sharp junctions between the rib sidewall and plate bottom, and rib sidewall and flat rib top. Typical prior art compartmented plate designs have radius fillets between the rib sidewall and plate bottom and a radius for the rib top. The plate of this invention disclosure also has compartmented rib dividers which abruptly terminate at the plate rim profile. This is in contrast to typical prior art compartmented plates which have large blending radii between the dividers and plate rim profile when viewed from the top.
The outer plate curvilinear profile consists of four radii having the preferred dimensions. The four radii design provides an ergonomic rim profile for ease of holding and carrying as will be appreciated from the discussion which follows.
The four radii plate profile and nonsymmetrical compartmented rib divider, having the desired angles between the dividers, sharp cross-sectional junctions and abrupt terminations at the plate rim profile as described in this invention disclosure, cooperate to provide greater rigidity and reduced buckling tendency.
Flange patterning can also be added to the product for visual or tactile purposes as noted above; however, the flange patterning should be chosen in a manner such that it does not interfere with the preferred compartment divider design.
In particularly preferred aspects of the present invention there is provided a three compartment disposable plate comprising a substantially planar bottom portion, a sidewall portion extending about the periphery of said bottom portion and projecting upwardly therefrom, a flange portion extending outwardly from said sidewall portion and a divider portion configured so as to segment said plate into three compartments of differing volume. The divider portion has a central junction portion and three ribs extending outwardly therefrom, a first rib, a second rib and a third rib; each of the ribs projecting upwardly from said bottom portion and extending from said central junction portion to the sidewall portion. Each of the ribs is substantially angularly joined to the bottom portion and the sidewall portion. A first included angle between the first and second ribs differs from a second included angle between the second and third ribs. A third included angle between the first and third ribs differs from said first and second included angles. Preferably, the first and second included angles, in the aggregate, total more than about 200 degrees, while the first included angle is from about 90 to about 110 degrees and the second included angle is from about 115 to about 135 degrees. The third included angle is preferably from about 125 to about 145 degrees.
In preferred embodiments, the first, second and third ribs have a substantially flat top portion, wherein the substantially flat top portion of the ribs is substantially angularly joined to a pair of upwardly projecting rib walls. The ratio of the diameter of the plate to the widths of the substantially flat top portions of the ribs is generally from about 55 to about 110, and more preferably the ratio of the diameter of the plate to the widths of the substantially flat portions is from about 65 to about 90.
In another preferred embodiment there is provided a three compartment disposable plate comprising a substantially planar bottom portion, a sidewall portion extending about the periphery of the bottom portion and projecting upwardly therefrom, a flange portion extending outwardly from the sidewall portion and a divider portion configured so as to segment the plate into three compartments of differing volume. The divider has a central junction portion and three ribs extending outwardly therefrom, a first rib, a second rib and a third rib; each of the ribs projecting upwardly from the bottom portion and extending from the central junction portion to the sidewall portion. Each of the ribs is substantially angularly joined to the bottom portion and the sidewall portion. A first included angle between said first and second ribs differs from a second included angle between the second and third ribs and a third included angle between the first and third ribs differs from the first and second included angles. The plate is formed of a mineral-filled polyolefin sheet and is characterized by a profile extending from the bottom portion to the outer edge of the flange, wherein changes in direction of the profile are perpetrated by way of a plurality of arcuate portions, each of the arcuate portions having a radius of curvature and wherein further, the ratio of the length of each of the radii of curvature to the diameter of the plate is at least about 0.02. Generally, the ratio of each of the radii of curvature to the diameter of said plate is at least about 0.03, and preferably, at least about 0.035.
The plate generally has a wall thickness of from about 10 to about 80 mils, and more preferably a wall thickness of from about 15 to about 25 mils.
In still yet another particularly preferred embodiment, the disposable plate has a wall thickness from about 10 to about 80 mils and consists essentially of from about 40 to about 90 percent by weight of a polypropylene polymer, from about 10 to about 60 percent by weight of a mineral filler, from about 1 to about 15 percent by weight polyethylene, from about 0.1 to about 5 weight percent titanium dioxide and optionally includes a basic organic or inorganic compound comprising the reaction product of an alkali metal or alkaline earth element with carbonates, phosphates, carboxylic acids as well as alkali metal and alkaline earth element oxides, hydroxides, or silicates and basic metal oxides, including mixtures of silicon dioxide with one or more of the following oxides: magnesium oxide, calcium oxide, barium oxide, and mixtures thereof.
The basic organic or inorganic compound may comprise calcium carbonate present in an amount of from about 5 to about 20 weight percent; whereas, polyethylene may be present from about 2.5 to about 15 percent by weight or from about 4 to about 5 weight percent.
Titanium dioxide is present generally from about 0.1 to about 3 weight percent, preferably from about 0.25 to about 2 percent by weight and is present in an amount of at least about 0.5 percent by weight in most cases. Wall caliper of from about 10 to about 50 mils are typical, while a wall caliper of from about 15 to about 25 mils is preferred. Mica is a preferred filler while a particularly preferred polypropylene polymer is isotactic polypropylene with a melt index of from about 0.3 to about 4 and preferably a melt flow index of about 1.5 in many cases. The polyethylene may be HDPE or LLDPE.
In still further aspects of the invention there is provided a disposable plate formed from a mineral-filled polyolefin sheet comprising: a substantially planar bottom portion; a first rim portion extending outwardly therefrom, the first rim portion being upwardly convex and subtending a first arc with a first radius of curvature; a second rim portion joined to the first rim portion, and extending outwardly therefrom, the second rim portion being downwardly convex, subtending a second arc with a second radius of curvature; a third rim portion joined to the second rim portion and extending outwardly therefrom, the third rim portion being downwardly convex, subtending a third arc with a third radius of curvature. The second and third rim portions form a sidewall portion. A fourth rim portion is joined to the third rim portion and extends outwardly therefrom, the fourth rim portion being downwardly convex subtending a fourth arc having a fourth radius of curvature. The length of the second arc of the second rim portion is substantially less than the length of the fourth arc of the fourth rim portion which, in turn, is substantially less than the length of the first arc of the first rim portion. The fourth radius of curvature of the fourth rim portion is less than the third radius of curvature of the third rim portion which, in turn, is less than the second radius of curvature of said second rim portion. The angle of the first arc is greater that about 55 degrees and the angle of the third arc is greater than about 45 degrees. The plate further includes a divider portion configured so as to segment said plate into three compartments of differing volume, the divider portion having a central junction portion and three ribs extending outwardly therefrom, a first rib, a second rib and a third rib. Each of the ribs projects upwardly from the bottom portion and extends from the central junction portion to the sidewall portion. Each of the ribs is substantially angularly joined to the bottom portion and the sidewall portion. A first included angle between the first and second ribs differs from a second included angle between the second and third ribs and a third included angle between the first and third ribs differs from the first and second included angles.
In general, the angle of the fourth arc is less than about 75 degrees. Preferably, the length of the first arc is substantially equivalent to the length of the third arc and the first radius of curvature of the first arc is substantially equivalent to the third radius of curvature of the third arc. The height of the center of curvature of the first rim portion above the plane of the bottom portion is substantially less than the distance by which the center of curvature of the second rim portion is below the plane of the bottom portion, whereas the horizontal displacement of the center of curvature of the second rim portion from the center of curvature of the first rim portion is at least about twice the first radius of curvature of the first rim portion. The height of the center of curvature of the third rim portion above the plane of the bottom portion is typically less than the height of the center of curvature of the fourth rim portion above the plane of the bottom portion, whereas the horizontal displacement of the center of curvature of the second rim portion is located outwardly from the center of curvature of both the third and fourth rim portions.
Most preferably, the height of the center of curvature of the third rim portion above the plane of the bottom portion is less than about 0.3 times the radius of curvature of the fourth rim portion and the height of the center of curvature of the fourth rim portion above the plane of the bottom portion is at least about 0.4 times the first radius of curvature of the first rim portion. The ratio of the length of the fourth radius of curvature to the diameter of the plate is preferably at least about 0.03, while the ratio of the length of the third radius of curvature to the diameter of the plate is at least about 0.050. The ratio of the length of the second radius of curvature to the diameter of the plate is generally at least about 0.2, while the ratio of the length of the first radius of curvature to the diameter of the plate is at least about 0.045.
In particularly preferred embodiments the length of the first arc is substantially equivalent to the length of the third arc and the length of the radius of curvature of the first arc is substantially equivalent to the length of the radius of curvature of the third arc.